1. Field of the Invention
The present invention relates to a tooth-fixing member used for fixing teeth which are loose due to periodontal diseases like pyorrhea alveolaris, and also to a method of fixing teeth with the fixing member.
2. Description of Related Art
As the periodontal tissue is successively damaged from the circumference of gingiva and alveolar bone gradually recedes in the course of periodontitis, teeth in the lesion of periodontitis become loose; this is a typical symptom of pyorrhea alveolaris. There are mainly two treatment procedures for teeth in pyorrhea alveolaris: extraction of a tooth which is extremely loose and of no use; and fixation of a tooth, which is loose but has some chance to survive, to an adjacent tooth with no or only slight looseness.
Fixation of a loose tooth to an adjacent tooth is generally implemented with metal wire. In concrete terms, target teeth, that is, a loose tooth, and its adjacent tooth, are tied with metal wire having sufficient elasticity and are then exposed to loading due to bending or tension of the metal wire so as to be securely fixed.
The method mentioned above, however, has some drawbacks; fastening target teeth with metal wire is both labor and time consuming; loading applied to the teeth gives a patient persistent pain and uncomfortable feeling; and the metal wire is undesirably seen whenever the patient opens the mouth.
Some methods of correcting the dental arch with shape memory alloy have been proposed; for example, Japanese Patent Laid-Open No. 49-50790 and No. 58-44047. An example of such method is briefly explained. An orthodontic member of shape memory alloy wire is processed through heat treatment so as to have a desirable shape to give the anatomically favorable dental arch in parent phase. The processed orthodontic member is fit on the dental arch of a patient at relatively low temperatures and is then heated to regain the original shape, thereby correcting the dental arch by taking advantage of its elastic force. While there are several disclosures regarding such orthodontic members of shape memory alloy, application of shape alloy metal to a tooth-fixing member has not yet been proposed.